118 research outputs found
Application of the Gadolinium Isotopes Nuclei Neutron-Induced Excitation Process
The possibility of transformation of energy of fast and epithermal neutrons to energy of coherent photon radiation at the expense of a neutron pumping of the active medium formed by nucleus with long-living isomerous states is theoretically described. The channel of the nucleus formation in isomeric state as a daughter nucleus resulting from the nuclear reaction of neutron capture by a lighter nucleus is taken into consideration for the first time. The analysis of cross sections’ dependence of radiative neutron capture by the nuclei of gadolinium isotopes Gd155 and Gd156 is performed. As a result, it is stated that the speed of Gd156 nuclei formation exceeds the speed of their “burnup” in the neutron flux. It is provided by a unique combination of absorbing properties of two isotopes of gadolinium Gd155 and Gd156 in both thermal and resonance regions of neutron energy. Conditions required for making isotope nuclei excited by forward neutron scattering on nuclei and for storing nuclei in excited states are formulated. The possibility of excess energy accumulation in the participating medium created by the nuclei of the pair of gadolinium isotopes Gd155 and Gd156 due to formation and storage of nuclei in isomeric state at radiative neutron capture by the nuclei of the stable isotope with a smaller mass is shown. It is concluded that when the active medium created by gadolinium nuclei is pumped by neutrons with the flux density of the order of 1013 cm−2 s−1, the condition of levels population inversion can be achieved in a few tens of seconds. The wave length of the radiation generated by the medium is 0.0006 nm
Adenocarcinoma of the lung with rare insertion mutation in egfr exon 19 that had partial response to gefitinib: a case report
Aim: Classic activating mutations L858R and deletions in exon 19 (19del) in the gene for epidermal growth factor receptor (EGFR) are associated with sensitivity of the non-small cell lung cancer (NSCLC) to therapy with tyrosine kinase inhibitors (TKI). Insertions in EGFR exon 19 (19ins) are rare mutations in NSCLC; response of cases with 19ins to TKI is not well studied. Here we report a case of NSCLC with 19ins in a Russian patient who was treated with gefitinib. We also overview cases of 19ins reported in the literature. Case description: A 48 years old female Russian patient was diagnosed with adenocarcinoma of the lung (T3N2M1, stage IV). Mutation 19ins was detected in the tumor biopsy by fragment analysis and genotyped by Sanger sequencing as p.I744_K745insKIPVAI. Treatment with gefitinib (250 mg/day) resulted in clinical and radiological improvements scored as partial response that lasted 12 months. Conclusion: Treatment with gefitinib of lung adenocarcinoma that carries mutation EGFR 19ins can result in durable response
The problems of utilizing graphite of stopped graphite-uranium reactors
A list of radioactive nuclides, the activity of which forms the main part of total activity of graphite stack and graphite elements of the construction of stopped industrial graphite-uranium reactors has been defined. The analysis of activity part contributed by these nuclides at different moments of time after stopping reactor was carried out. A set of construction graphite elements, in which there is a possibility of self-sustaining release of the energy stored (Wigner's energy) was determined. It was stated that the most value of the Wigner's energy is achieved in graphite constructions operated in low-temperature region or at high values of flux densities of damaging neutrons and concurrent gamma radiation
Estimation of solvate sphere sizes of cation aquacomplexes in salt solution
The problem of determination of sizes of supermolecular formation (a cluster) consisting of the molecules of water coordinated around a central ion has been analytically solved. The obtained values of the cation aquacomplex point out the possibility of exciting their drift by applying asymmetric electric field with frequency in the range from hundreds of Hz to units of kHz on aqueous salt solution. Drift parameters are determined by inertial properties of aquacomplexes that allows dividing them
Gamma-spectrometric control method of activity and nuclide composition of low-active solid radioactive waste
The gamma-spectrometric control method of low-active solid radioactive waste, based on direct measurement of activity and nuclide composition has been developed. The measurements were carried out in the geometry of standard steel container of 200 l. volume, where low-active wastes were placed. To take into account distribution non-homogeneities of solid waste over the geometry measured a special rotating platform was used, the low-active radioactive wastes being placed on it. Metrological certification was performed and the main errors of this method for 95 % of confidence probability were determined
The use of wheatgrass (<i>Thinopyrum intermedium</i>) in breeding
Wheatgrass (Th. intermedium) has been traditionally used in wheat breeding for obtaining wheat-wheatgrass hybrids and varieties with introgressions of new genes for economically valuable traits. However, in the 1980s in the United States wheatgrass was selected from among perennial plant species as having promise for domestication and the development of dual-purpose varieties for grain (as an alternative to perennial wheat) and hay. The result of this work was the creation of the wheatgrass varieties Kernza (The Land Institute, Kansas) and MN-Clearwater (University of Minnesota, Minnesota). In Omsk State Agrarian University, the variety Sova was developed by mass selection of the most winter-hardy biotypes with their subsequent combination from the population of wheatgrass obtained from The Land Institute. The average grain yield of the variety Sova is 9.2 dt/ha, green mass is 210.0 dt/ ha, and hay is 71.0 dt/ha. Wheatgrass is a crop with a large production potential, beneficial environmental properties, and valuable grain for functional food. Many publications show the advantages of growing the Kernza variety compared to annual crops in reducing groundwater nitrate contamination, increasing soil carbon sequestration, and reducing energy and economic costs. However, breeding programs for domestication of perennial crops are very limited in Russia. This paper presents an overview of main tasks faced by breeders, aimed at enhancing the yield and cultivating wheatgrass efficiency as a perennial grain and fodder crop. To address them, both traditional and modern biotechnological and molecular cytogenetic approaches are used. The most important task is to transfer target genes of Th. intermedium to modern wheat varieties and decrease the level of chromatin carrying undesirable genes of the wild relative. The first consensus map of wheatgrass containing 10,029 markers was obtained, which is important for searching for genes and their introgressions to the wheat genome. The results of research on the nutritional and technological properties of wheatgrass grain for the development of food products as well as the differences in the quality of wheatgrass grain and wheat grain are presented
Modeling of the Compression Process of Technological Gas in the N-400-21-1C Centrifugal Compressor
В настоящей работе представлена разработанная численная модель центробежного компрессора природного газа, описаны результаты моделирования течения в его проточной части, представлено сравнение с экспериментальными данными.In this paper we present the developed numerical model of a natural gas centrifugal compressor, describe the results of flow simulation in its flow section, and compare it with the experimental data
Electrophysical methods of separation of metal cations in the moving salts solution
The results of experiments on the excitation of the phenomenon of selective drift of solvated ions under the influence of an external "asymmetric" electric field to the circulating solution of calcium chloride and magnesium salts in a polar liquid dielectric - water are shown. The purpose of the experiments was to determine the influence of the field frequency and amplitude of the field strength on the excitation phenomenon, and the study of the operating characteristics of the testing apparatus - a dividing cell. The dependences of the separation efficiency of solvated cations from the frequency of the external field and the excitation threshold of the phenomenon from the field strength in the separation cell are defined
Ions separation under external periodic electric field action on salts solutions in polar dielectric liquids
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